Stator casing and blade assembly



Oct. 21, 1958 E. P. WARNKEN STATOR CASING AND BLADE ASSEMBLY Filed Dec. 2, 1954 4 Sheets-Sheet 1 IN VHV TOR.

BY I WW Afiys.

Oct. 21, 1958 v WARNKE'N 7 2,857,093

STATOR CASING AND BLADE ASSEMBLY Filed Dec. 2, 1954 4 Sheets-Sheet 2 IN V EN TOR.

I j g ELMER P. MRNHE/v Oct. 21,1958 WARNKEN 2,857,093

STATOR CASING AND BLADE ASSEMBLY Filed Dec. 2, 11,954 V r 4 Sheets-Sheet 3 IN VEN TOR.

Oct. 21, 1958 E. P. WARNKEN 3 TATOR CASING AND BLADE ASSEMBLY I I Filed Dec. 2, 1954 ASheets-Sheet 4 IN VEN TOR. ELMER R WARN/(EN United States Patent STATOR CASING BLADE ASSEMBLY Elmer P. Warnken, Cincinnati, Ohio, assignor to CincinnatiTesting.& Research'Laboratories, Cincinnati, Ohio, a partnership Application December 2, 1954, Serial No. 472,644

1 Claim. ((31. 230-133) stator casing which can be constructed without need for complex machiningoperations.

A further object of this invention is 'to provide a stator casing and blade assembly in which individual blades can readily be mounted and from which blades can readily be removed for servicing.

A further object of this invention is to provide a stator casing and blade assembly in which blades having wedgeshaped root end portions are received in slotted segmentshaped members which may be assembled or formed integrally with the casing, the wedge-shaped end of each blade being held firmly in the slot thereof.

A further object of this invention is to provide such an assembly in which the blades extend through segmental members disposed in apertures or slots in an outer casing member, the root ends being larger than the apertures, the root ends of the blades being clamped between the inner wall of the casing and said segmental members.

A further object of this invention is to provide a stator casing and blade assembly in which the casing itself is provided with apertures through which the blades extend, the root ends of the blades being larger than the apertures and being firmly secured therein by an outer wrapping or retaining web or strap embracing the casing and holding the blades firmly in position.

The above and other objects and features of the invention will in part be apparent and will in part be obvious to those skilled in the art to which this invention pertains, from the following detailed description, and the drawings, in which:

Figure 1 is a perspective view showing a half section of a casing for an axial fiow compressor of an aircraft engine;

Fig. 2 is an enlarged view in section taken on line II-II of Fig. l with stator blades mounted therein;

Fig. 3 is a perspective view partly in section showing a segment and blade assembly embodied in the casing section of Fig. 2;

Fig. 4 is a partial view in section taken on line IVIV in Fig. 2;

Fig. 5 is a perspective view showing a portion of a stator casing including two half sections constructed in accordance with another embodiment of this invention;

Fig. 6 is an enlarged partial view in section taken on line VIVI of Fig. 5 showing details of mounting the blades in the casing section;

Fig. 7 is a fragmentary plan view of a portion of the casing looking in the direction of the arrows VIIVII in Fig. 6; and

Fig. 8 is a view in section taken along the line VIII-VIII in Fig. 6.

In Fig. 1 is illustrated a half-section 10 of a casing of 2,857,093 1:Patenied" 0ct. 2 1, 1958 .2 general frusto-con'ieal shape provided with flanges "11 at the part line thereof (only one of which is shown) ,provided with bolt holes 11: for use in attaching the halfsection -10-to anothers'im'ilar' half-section to 'form a complete'casing section. In addition, flanges 12 and 13 are provided at opposite ends-of the half-section for 'use in attaching it to adjacent casing sections of an axial lflow compressor,

As shown in Fig. 2, 'the inner wall of half-section "10 is provided with a plurality of spaced 'annular grooves 14. Each groove 14 receives a segment 17 provided with a plurality ofblades 18. i

A segment 17 with its complement "of blades '18 is illustrated in Fig. '3. As there illustrated, each blade 18 includes a main or airfoil portion 19 and a root end portion 21. The root end portion 2'1-of each blade is of wedge-shape, the -sidesof the wedge diverging from the airfoil portion f the blade. The segment 17 is provided with wedge-shaped apertures through which the blades are inserted and "in which the portions 21 are received and retained. In "addition, the segment is provided with a series-of threaded holes '23, in the threads of which 'a helical member 24 of the *heli-cdil type is received. The h'eli-coil 24 registers with the threads of a bolt 26. In Fig. 4, the size of the heli-coil is exaggerated for clarity of showing.

As shown in Fig. 2, the segments 17 are held in the grooves 14 by means of the bolts 26. The bolts are received in metal bushings 26' located in the bolt holes in the casing 10, as shown.

As shown in Fig. 4, the outer end 31 of the wedge-shaped root 21 of each blade projects outwardly of the segment 17 a short distance and engages the base of the groove 14, so that when the bolts 26 are drawn tight, the root portions 21 are wedged firmly in position in the apertures 22 of segment 17.

The casing and the segments may be formed of metal or of resin-impregnated glass fabric. Since there is no undercutting at the grooves, the casing may be molded and requires little or no machining. Preferably the casing and the segments are formed of resin-impregnated fibre glass, or the like, and the blades may be formed of similar material, and all the major parts are molded to shape.

In the device illustrated in Figs. 14 inclusive, stator blades of a cantilever type are shown. However, if desired, the blades may be stayed at the inner ends by a support ring or shroud of the type which is common in axial flow compressors.

In Figs. 5-8 inclusive is shown a section of a stator casing and blade assembly constructed in accordance with another embodiment of the invention. The stator casing section of Fig. 5 includes two half-sections 36 and 37. The half-sections are held together by bolts 38 which extend through flanges 39 and 41 on the casing half-sections. As shown in Figs. 5 and 6, each half-section is provided with a plurality of apertures or slots 42. The slots 42 are of Wedge-shape in section as shown in Fig. 8. Each of these slots can receive a blade 43 which may be similar in construction to one of the blades already described. The blades project through the walls of the casing sections with the root ends of the blades being received in the openings 42 and a small portion of each root end extending outwardly of the casing.

The blades are held in place in the slots 42 by straps 44. Each strap includes an upper portion 44a and a lower portion 44b. The ends of the upper and lower portions of each strap are bent outwardly to form tabs 46 and 47. The tabs 46 and 47 are provided with aligned openings for receiving bolts 48 which draw the straps tightly against the wall of the casing and against the outer ends of the blades to hold the blades in position with the airfoil portions of the blades projecting into the casing, as shown in Figs. 6 and 8. The straps are mounted on the casing section between lines of lugs 51 which hold the straps in alignment with the rows of slots 42.

The casing sections' of the device illustrated in Figs. -8 may be molded of resin-impregnated glass fabric, or the like, and the blades may be of similar construction. However, both the casing sections and the blades may be formed of other materials such as light strong metals, or the like, if preferred. The wrapping strap may be stainless steel or other material of high tensile strength.

The stator casing and blade assemblies illustrated in the drawings, and described above, are subject to structural modification without departing from the spirit and scope of the appended claim.

Having described my invention, what I claim as new, and desire to secure by Letters Patent is:

A stator casing and blade assembly for an axial flow compressor which comprises a plurality of stator blades, each of said blades having an airfoil portion and a root end portion, the root end portion being of wedge shape with the wedge diverging from the airfoil portion, a hollow casing having complementary portions, each of said casing portions having a convex outer surface, there being flanges on the adjoining edges of the casing portions, bolts extending through openings in the flanges of the casing portions, nuts on the bolts for attaching the flanges of the portions of the casing together, there being a plurality of outwardly expanding wedge-shaped slots in the casing portions for receiving the root ends of the blades, with a portion of each blade extending outwardly of the casing, a split strap embracing the convcex surface of the casing and engaging the outwardly extending portions of the blades, said strap having a pair of portions, there being one strap portion for each of the casing portions, flanges on the ends of the strap portions, adjacent flanges of the strap portions being on opposite'sides of flanges of the casing portions, and other bolts extending through openings in the adjacent ends of the strap portions and nuts on the other bolts for drawing the flanges of adjacent ends of the strap portions toward each other, to cause the strap to tightly engage the blades and urge the wedge-shaped portion of each blade firmly into the slot associated therewith.

References Cited in the file of this patent V UNITED STATES PATENTS 1,080,825 Fryer Dec. 9, 1913 2,640,319 Wislicenus June 2, 1953 FOREIGN PATENTS 375,059 France May 2, 1906 572,859 Great Britain Oct. 26, 1945 599,391 Great Britain Mar. 11, 1948 660,383 Great Britain Nov. 7, 1951 702,549 Great Britain J an. 20, 1954 

